Two‐dimensional liquid chromatography analysis of all‐trans‐, 9‐cis‐, and 13‐cis‐astaxanthin in raw extracts from Phaffia rhodozyma

Abstract

An effective two‐dimensional liquid chromatography method has been established for the analysis of all‐trans‐astaxanthin and its geometric isomers from Phaffia rhodozyma employing a C18 column at the first dimension and a C30 column in the second dimension, connected by a 10‐port valve using the photo‐diode array detector. The regression equation of astaxanthin calibration curve was established, and the precision and accuracy values were found to be in the range of 0.32–1.14% and 98.21–106.13%, respectively. By using two‐dimensional liquid chromatography, it was found that day light, ultrasonic treatment, and heat treatment have significant influence on the content of all‐trans‐astaxanthin in the extract from P. rhodozyma due to the transformation of all‐trans‐astaxanthin to cis‐astaxanthin. The day light and ultrasonic treatments more likely transform all‐trans‐astaxanthin to 9‐cis‐astaxanthin, and the thermal treatment transforms all‐trans‐astaxanthin to 13‐cis‐astaxanthin. These results indicate that the two‐dimensional liquid chromatography method can facilitate monitoring astaxanthin isomerization in the raw extract from P. rhodozyma. In addition, the study will provide a general reference for monitoring other medicals and bioactive chemicals with geometric isomers.

Astaxanthin Isomers: A Comprehensive Review of Isomerization Methods and Analytic Techniques

“…This method has shown to have more precise selectivity and higher separation efficiency when quantifying a small number of selected compounds in a very complex matrix. 89 Currently, astaxanthin content is analyzed by 1-D reversed phase HPLC. However, the presence of some impurities in the raw extracts of astaxanthin negatively affected the accuracy of analytical procedures, due to coelution with astaxanthin in the case of 1-D HPLC procedures.…”

“…For example, Du et al (2012) quantified astaxanthin obtained from P. rhodozyma and H. pluvialis as well as that derived from chemical synthesis; Li et al (2021) also successfully isolated (3S,3′S) astaxanthin from adonis flowers. 89,95 HPLC technology has also been successfully applied in the analysis of free and esters. In 1997, researchers have successfully separated different astaxanthin esters from Haematococcus lacustris by HPLC with the mobile phase consisting of methanol (69.0%), dichloromethane (17.0%), acetonitrile (11.5%), and water (2.5%) on a C18 column.…”

“…This is an established approach for the analysis of geometrical isomers separated from extracts without prior purification (Figure ). This method has shown to have more precise selectivity and higher separation efficiency when quantifying a small number of selected compounds in a very complex matrix …”

“…rhodozyma and H. pluvialis as well as that derived from chemical synthesis; Li et al (2021) also successfully isolated (3 S ,3′ S ) astaxanthin from adonis flowers. , …”

Residue measurement of pendimethalin in tobacco by using heart‐cutting two dimensional liquid chromatography coupled with tandem mass spectrometry

“…Compared to the widely used 1D chromatographic methods, 2D‐LC greatly improved the peak capacity. By coupling two different columns, heart‐cutting 2D‐LC method could remove interference compounds effectively [19‐21]. In our work, a heart‐cutting RP/RP–2D‐LC–MS/MS method was developed for the quantification of pendimethalin.…”